textproduct: Rapid City

KEY MESSAGES

- Hot and dry conditions continue for most of the region today and Friday, before trending cooler and more moist for the weekend.

- Elevated to near-critical fire weather conditions continue to result, with a RED FLAG WARNING now issued from Weston County down across the southwestern South Dakota plains/southern Black Hills Friday as increasing winds overlap the dry conditions.

- Next organized storm system remains expected this weekend, with the best chance of showers Saturday night through Sunday night.

DISCUSSION

(This Evening Through Thursday) Issued at 257 PM MDT Thu Sep 10 2026

A focus on hot, dry, and breezy conditions with attendant fire weather concerns today into Friday quickly switches over to a fresh storm system for the weekend with increasing moisture and decreasing temperatures. More on the fire side of things in the FIRE WEATHER section below.

No risk of a shower anywhere today. High resolution models are hinting at cloud buildups and perhaps a few showers as early as late Friday afternoon into Friday night, but instability (outside of DCAPE) will be extremely limited and the low-levels will still lean quite dry per model forecast soundings and HREF means. It's possible this activity manifests as more virga than bonafide showers with little rainfall reaching the ground. That said, broadbrushed light PoPs across much of the CWA (especially west of a line from Faith to Pine Ridge) Friday evening to cover any development, with PoPs focusing more north of Gillette and Rapid City up to the MT/ND borders overnight into Saturday morning. Breezy conditions are also forecast Friday as the pressure gradient tightens and a fairly diffuse cool front moves across the region from the northwest, shifting winds from the west to north with time. Gusts as high as 30-40 MPH will be possible across much of the region.

The potential for showers will increase much more Saturday night and Sunday...but as we often see with guidance on these systems as they get closer in time, the potential for substantial rainfall has trended down. Storm totals may only reach a few hundredths of an inch across northeastern Wyoming...to 0.10" or so across the Black Hills and Rapid City...to perhaps 0.50" in our far eastern counties across the central South Dakota plains. The magnitude of our cooldown has also moderated (sorry Fall fans!)...with high temperatures Saturday, Sunday, and Monday now expected to generally hold in the 70s (instead of 60s) outside of higher terrain in the Black Hills. Breezy conditions are possible Sunday and Monday, especially across the northwestern South Dakota plains. Generally drier conditions are expected by Monday and Tuesday, although broad troughing to our west/southwest and precipitation forecast to our south across Nebraska suggest somewhat low confidence at this juncture.

AVIATION

(For the 00Z TAFS Through 00Z Friday Evening) Issued At 504 PM MDT Thu Sep 10 2026

VFR conditions are expected through the period. Gusty northwesterly winds will develop across western South Dakota late Friday morning (~11/15z) behind a cool front, with gusts up to 30 to 35 kts. Isold shra/ts are possible in the late afternoon and early evening Friday across the western third. Expect gusty winds INVOF any shra/ts.

FIRE WEATHER

Issued At 257 PM MDT Thu Sep 10 2026

The hottest and driest conditions of the week are in progress today, with minimum afternoon relative humidity values now approaching their forecast lows of 8-18 percent and high temperatures reaching the low 90s. The limiting factor for reaching critical thresholds today are the winds, with gusts generally holding at 15-25 MPH. Very poor overnight RH recovery remains expected tonight into Friday morning from the Black Hills and Fall River County area westward across northeastern Wyoming, with RHs only increasing to 25-35 percent. Friday...the hot temperatures and low RH values will start to moderate a bit from the northwest as a somewhat diffuse cool front crosses into the region, but will remain similarly hot/dry south and east of the Black Hills overlapping with winds increasing to 15-25 MPH with gusts 30-40 MPH across most of the region...gradually shifting from west to north over the course of the day due to the aforementioned front. A RED FLAG WARNING has now been issued where these winds will overlap with lingering driest conditions... generally from Weston County down across the southwestern South Dakota plains and southern Black Hills from 1 PM to 7 PM. NBM RH values are running a bit high everywhere compared to nearly all other sources of guidance including ensembles, in addition to some uncertainty as to the exact timing and impact of the front coming in from the northwest. Nudged the RH forecast a bit lower across southern/eastern portions of the CWA with this in mind. Grassland Fire Danger will range from Very High to Extreme across most of the region, especially in response to the increased winds.

High resolution models are hinting at cloud buildups and perhaps a few showers late Friday afternoon into Friday night, but instability will be extremely limited and the low-levels will still lean quite dry per model forecast soundings and HREF means. It's possible this activity manifests as more virga than bonafide showers with little rainfall reaching the ground. Wetting rains are certainly not expected at this time. That said, broadbrushed light PoPs across much of the CWA (especially west of a line from Faith to Pine Ridge) Friday evening to cover any development, with PoPs focusing more north of Gillette and Rapid City up to the MT/ND borders overnight. The potential for showers will increase much more Saturday night and Sunday in association with our next approaching low pressure system, with the weekend generally trending cooler and more moist. That said, total weekend QPF totals are currently only expected to range from a few hundredths of an inch across northeastern Wyoming to perhaps 0.50" over the central South Dakota plains. Watch for potentially breezy conditions looking ahead to Sunday and Monday...especially across the northwestern South Dakota plains.

UNR WATCHES/WARNINGS/ADVISORIES

SD...Red Flag Warning from 11 AM to 7 PM MDT Friday for SDZ321-322- 325-326-332-333. WY...Red Flag Warning from 11 AM to 7 PM MDT Friday for WYZ317.